U.S. patent number 9,222,593 [Application Number 13/663,267] was granted by the patent office on 2015-12-29 for solenoid actuated pilot valve for irrigation system valve.
This patent grant is currently assigned to Hunter Industries, Inc.. The grantee listed for this patent is Hunter Industries, Inc.. Invention is credited to Michael L. Clark.
United States Patent |
9,222,593 |
Clark |
December 29, 2015 |
Solenoid actuated pilot valve for irrigation system valve
Abstract
A solenoid actuated pilot valve includes a pilot valve housing
defining a pilot valve chamber and a solenoid. The solenoid
includes and end cap connected to the pilot valve housing, a
reciprocable plunger, and a piston having a shaft with a first end
connected to and end of the plunger and a second end connected to a
piston head. The end cap has a bore through which the shaft of the
piston reciprocates and a first port separate from the bore. A
first seal on a first side of the piston head is provided for
sealing a first end of the first port. A second seal on a second
side of the piston head is provided for sealing a first end of a
second port in the pilot valve housing.
Inventors: |
Clark; Michael L. (San Marcos,
CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hunter Industries, Inc. |
San Marcos |
CA |
US |
|
|
Assignee: |
Hunter Industries, Inc. (San
Marcos, CA)
|
Family
ID: |
40622587 |
Appl.
No.: |
13/663,267 |
Filed: |
October 29, 2012 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K
31/402 (20130101); F16K 7/075 (20130101); F16K
31/0627 (20130101); F16K 31/02 (20130101); Y10T
137/86614 (20150401); Y10T 137/86895 (20150401); F16K
11/044 (20130101); F16K 11/04 (20130101); Y10T
137/86686 (20150401) |
Current International
Class: |
F16K
31/06 (20060101); F16K 31/02 (20060101); F16K
11/04 (20060101); F16K 11/044 (20060101) |
Field of
Search: |
;137/625.64,625.65,625.25,625.27 ;251/129.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Declaration of Michael L. Clark regarding SBH 086 Solenoid and
Manifold Assembly sold by Grizzle & Hunter Plastic, Inc., (2
pgs) and attached Exhibit A entitled "Pilot Valve Drawing, Grizzle
& Hunter SBH 086, 2004" (1 page). cited by applicant.
|
Primary Examiner: McCalister; William
Assistant Examiner: Paquette; Ian
Attorney, Agent or Firm: Knobbe, Martens, Olson & Bear,
LLP
Claims
We claim:
1. A solenoid actuated valve, comprising: a valve housing defining
a valve chamber having a first port, a second port, and a third
port, wherein the third port communicates with the valve chamber; a
solenoid positioned at least partially within the valve housing and
including a reciprocable shaft moveable between a first position
when the solenoid is energized and a second position when the
solenoid is not energized; a drive shaft positioned within the
valve housing, the drive shaft moved by an axial force of the
reciprocable shaft only when the reciprocable shaft is moved to the
second position; a head connected to the drive shaft and not
permanently connected to the reciprocable shaft, the head movable
within the valve chamber by the drive shaft and including a first
seal for sealing a first end of the first port when the solenoid is
energized and a second seal for sealing a first end of the second
port when the solenoid is not energized; and a biasing element
configured to bias the head to seal the first end of the second
port, wherein the valve head is positioned within a pilot valve
chamber and wherein the biasing element is positioned outside of
and fluidly separate from the pilot valve chamber; wherein the
drive shaft pulls the head toward the reciprocable shaft when the
solenoid is energized.
2. The valve of claim 1 wherein the first end of the first port
opens on an end surface of a guide sleeve attached to the solenoid,
and a second end of the first port opens on a side surface of the
guide sleeve.
3. The valve of claim 1 wherein the first seal and the second seal
are provided by opposite sides of an elastomeric cover that
surrounds the head.
4. The valve of claim 1, wherein the reciprocable shaft is moved
away from the head when the solenoid is energized.
5. The valve of claim 1, wherein the reciprocable shaft moves on an
actuation axis between the first position and the second position
and wherein the first end of the first port is spaced laterally
from the actuation axis.
6. The valve of claim 1, wherein the drive shaft has a first end
nearest the solenoid, a second end furthest from the solenoid, and
a drive shaft axis, wherein the drive shaft extends along the drive
shaft axis between the first and second ends of the drive shaft,
and wherein the drive shaft axis extends beyond the first and
second ends of the drive shaft and passes through the first end of
the second port and through the reciprocable shaft.
7. The valve of claim 1 wherein a first axis of the reciprocable
shaft of the solenoid and a second axis of the first port are
substantially parallel.
8. The valve of claim 7 wherein a third axis of the second port is
substantially co-axial with the first axis.
9. The valve of claim 1 wherein the reciprocable shaft and the head
are selectively operatively connected.
10. The valve of claim 9 wherein the reciprocable shaft and the
head are operatively connected in a non-energized position.
11. A solenoid actuated valve comprising: a valve housing; a
solenoid removably attached to the valve housing; a first port
facilitating fluid communication between an interior of the valve
housing and an exterior of the valve housing; a second port
facilitating fluid communication between the interior of the valve
housing and the exterior of the valve housing; a drive shaft
positioned within the valve housing and moveable between a first
position and a second position; a valve head connected to and
integral with the drive shaft configured to transition between a
first sealing position when the drive shaft is in the first
position and a second sealing position when the drive shaft is in
the second position, the valve head sealing a first end of the
first port when in the first sealing position and sealing a first
end of the second port when in the second sealing position; a
solenoid actuated shaft that has a first actuation position when
the solenoid is not energized and a second actuation position when
the solenoid is energized, the solenoid actuated shaft configured
to selectively abut and force the drive shaft to the second
position only when the solenoid actuated shaft is transitioned to
the first actuation position; a first biasing element biasing the
solenoid actuated shaft toward the first actuated position, wherein
the solenoid actuated shaft abuts the drive shaft and transitions
the drive shaft to the second position when the solenoid is not
energized; and a second biasing element biasing the drive shaft
toward the first position; wherein the solenoid actuated shaft
moves on an actuation axis between the first actuation position and
the second actuation position and wherein the first end of the
first port is spaced laterally from the actuation axis; and wherein
the valve head is positioned within a pilot valve chamber and the
second biasing element is positioned outside of and fluidly
separated from the pilot valve chamber.
12. The valve of claim 11, wherein the solenoid actuated shaft
disengages from the drive shaft when the solenoid is energized.
13. The valve of claim 11, wherein the drive shaft has a first end
nearest the solenoid, a second end furthest from the solenoid, and
a drive shaft axis, wherein the drive shaft extends along the drive
shaft axis between the first and second ends of the drive shaft,
and wherein the drive shaft axis extends beyond the first and
second ends of the drive shaft and passes through the first end of
the second port and through the solenoid actuated shaft.
14. A solenoid actuated valve comprising: a valve housing; a
solenoid connected to the valve housing and positioned at least
partially within the valve housing; a guide sleeve positioned at
least partially within the valve housing and including a bore; a
first port in a wall of the guide sleeve; a second port in a wall
of the valve housing; a valve head configured to transition between
a first sealing position wherein the valve head seals the first
port and a second sealing position wherein the valve head seals the
second port; a third port in a wall of the valve housing which
remains unsealed when the valve head is in the first sealing
position and when the valve head is in the second sealing position;
a drive shaft integral with the valve head and moveable along an
axis of the bore; a solenoid actuated shaft configured to axially
force the valve head to the second sealing position when the
solenoid is not energized, the solenoid actuated shaft spaced
further from the valve head when the solenoid is energized than
when the solenoid is not energized; and a biasing element
configured to apply a first biasing force to bias the valve head to
the first sealing position; wherein the valve head is positioned
within a valve chamber and wherein the biasing element is
positioned outside of the valve chamber and fluidly separate from
the valve chamber.
15. The valve of claim 14, wherein the solenoid actuated shaft is
biased toward the valve head with a second biasing force greater
than the first biasing force when the solenoid is not
energized.
16. The valve of claim 14, wherein the solenoid actuated shaft is
configured to move along an actuation axis when the solenoid
transitions between an energized state and a non-energized state,
and wherein the first port is spaced laterally from the actuation
axis.
17. The valve of claim 14, wherein the drive shaft has a first end
nearest the solenoid, a second end furthest from the solenoid, and
a drive shaft axis, wherein the drive shaft extends along the drive
shaft axis between the first and second ends of the drive shaft,
and wherein the drive shaft axis extends beyond the first and
second ends of the drive shaft and passes through the first end of
the second port and through the solenoid actuated shaft.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS AND PATENTS
This application is a continuation-in-part (CIP) of the similarly
entitled U.S. patent application Ser. No. 12/353,832 filed Jan. 14,
2009 of Michael L. Clark which will issue as U.S. Pat. No.
8,297,314 on Oct. 30, 2012. Said U.S. patent application Ser. No.
12/353,832 is in turn a CIP of U.S. patent application Ser. No.
11/472,964 filed Jun. 21, 2006, to of Michael L. Clark, which
issued as U.S. Pat. No. 7,503,346 on Mar. 17, 2009. The entire
disclosures of the aforementioned applications and patents are
hereby incorporated by reference. This application and the
aforementioned U.S. patents are owned by Hunter Industries, Inc.,
the assignee thereof.
FIELD OF THE INVENTION
The present invention relates to valves used to control the flow of
liquids, and more particularly, to solenoid operated valves
typically used to turn ON and OFF the flow of water in residential
and commercial irrigation systems.
BACKGROUND OF THE INVENTION
In a typical irrigation system a manually programmable electronic
controller selectively energizes a solenoid operated valve to cause
pressurized water to be delivered to a set of sprinklers connected
to a common buried PVC pipe. Each set of sprinklers is referred to
as a station or zone and is supplied with pressurized water by a
corresponding solenoid actuated valve. The solenoid actuated valve
typically has a clam shell or bonnet configuration exemplified in
U.S. Pat. No. 6,079,437 granted Jun. 27, 2000 to Beutler et al. and
assigned to Hunter Industries, Inc. In a bonnet valve, pressurized
upstream or inlet water passes via a small metering orifice in a
central metering body to a control chamber inside the upper clam
shell on the back side of a circular elastomeric diaphragm to apply
a closing pressure. This forces the periphery of a valve member
connected to the diaphragm against a valve seat. Water can be
vented from the control chamber through a small pilot valve passage
which is opened by a solenoid actuated pilot valve, which causes
the diaphragm and valve member to move upwardly and allow water to
flow freely through the main flow passage of the valve.
Another type of valve used in industrial and agricultural
applications, but not in residential and commercial irrigation
systems, is known as a sleeve valve and is exemplified in U.S. Pat.
No. 5,671,774 granted Sep. 30, 1997 to Klein et al. and assigned to
Nelson Irrigation Corporation. In a sleeve valve, a substantially
cylindrical elastomeric sleeve is surrounded by an outer
cylindrical rigid housing to define a control chamber between the
elastomeric sleeve and housing. The ends of the elastomeric sleeve
overlap a mandrel including opposing frusto-conical sections having
circumferentially spaced slots. A solenoid operated pilot valve can
release pressurized water from a control chamber to allow the
elastomeric sleeve to expand and uncover the slots, thereby
allowing water to flow freely through the main flow passage of the
sleeve valve.
A two-way solenoid actuated pilot valve typically includes a
solenoid whose spring biased plunger moves an elastomeric seal.
When the solenoid is de-energized the plunger pushes the
elastomeric seal against a pilot valve seat in a pilot valve
chamber, closing a passage that leads from the control chamber of
the main valve. This closes the main valve. When the solenoid is
energized, the plunger retracts and the elastomeric seal moves away
from the pilot valve seat, allowing pressurized liquid to leave the
control chamber through the passage, through the pilot valve
chamber and through a relief passage into the outlet of the main
valve. This opens the main valve. See U.S. Pat. No. 5,979,482
granted Nov. 9, 1999 to Scott and assigned to Hunter Industries,
Inc.
A three-way solenoid actuated pilot valve is used to switch between
two different sources and a common destination, and vice versa. An
elastomeric seal is moved against a first pilot valve seat when the
plunger is retracted and against a second pilot valve seat when the
plunger is extended. Valves used in residential and commercial
irrigation systems have used three way solenoid actuated pilot
valves. The power supplied to solenoid actuated valves used in
residential and commercial irrigation systems is relatively low.
This necessitates the use of relatively small pins and seals in
three way solenoid actuated pilot valves that are expensive to
manufacture and assemble. These delicate components require
significant precision for reliable operation and they are prone to
breakage.
SUMMARY OF THE INVENTION
In accordance with the present invention, a solenoid actuated pilot
valve includes a pilot valve housing defining a pilot valve chamber
having a first port and a second port. The pilot valve further
includes a solenoid having a reciprocable shaft. A head movable is
within the pilot valve chamber by the shaft of the solenoid. A
first seal on the head seals a first end of the first port when the
solenoid is in a first state and a second seal on the head seals a
first end of the second port when the solenoid is in a second
state.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary isometric view of a sleeve valve
incorporating a three-way solenoid actuated pilot valve in
accordance with an embodiment of the present invention. The coil of
the solenoid is not illustrated in this view.
FIG. 2 is an enlarged cross sectional view of a sleeve valve of
FIG. 1 illustrating the pilot valve in its valve closed position.
The coil of the solenoid is illustrated diagrammatically in this
view.
FIG. 3 is a view similar to FIG. 2 illustrating the pilot valve in
its open position.
FIG. 4 is an enlarged exploded sectional view of the solenoid
portion of the pilot valve of FIG. 1.
FIG. 5 is an isometric view of the sleeve valve of FIG. 1 with one
of its end caps unscrewed to reveal the inlet of the passage formed
in the sleeve valve housing that leads to the pilot valve
chamber.
FIGS. 6A and 6B are vertical sectional views illustrating a first
alternate embodiment of the present invention.
FIG. 7 is a vertical sectional view illustrating a second alternate
embodiment of the present invention.
FIG. 8 is an enlarge portion of FIG. 7.
DETAILED DESCRIPTION
A sleeve valve 10 (FIG. 1) includes a mandrel 12 (FIG. 2) with a
plurality of slots 14. A generally cylindrical elastomeric sleeve
16 surrounds the mandrel 12. A generally cylindrical rigid sleeve
valve housing 18 (FIG. 1) surrounds the elastomeric sleeve 16 and
defines a control chamber (not illustrated) between the elastomeric
sleeve 16 and the sleeve valve housing 18 (FIG. 1). A pilot valve
20A is mounted to the sleeve valve housing 18 for opening and
closing the sleeve valve 10 by turning ON and OFF a low voltage AC
control signal to a non-latching solenoid 20B. The twenty-four volt
AC signal is applied via a pair of wires (not illustrated)
connected between a coil 22 (FIG. 2) of the solenoid 20B and an
irrigation controller (not illustrated). A generally cylindrical
end cap 24 of the pilot valve 20A has male threads so that it can
be connected to the sleeve valve housing by screwing it into a
female threaded pilot valve housing 26 integrally formed with the
sleeve valve housing 18. The longitudinal axis of the pilot valve
housing 26 is substantially orthogonal to the longitudinal axis of
the sleeve valve housing 18. Upper and lower O-rings 27 are seated
in external grooves formed in the end cap 24 and are deformed by
the inner walls of the pilot valve housing 26 to provide a
water-tight seal. By way of example, the elastomeric sleeve 16 may
be molded from material such as EPDM, PVC or silicone and the rigid
housing 18, end cap 24, and pilot valve housing 26 may be molded
from material such as ABS plastic.
The function of the pilot valve 20A is to supply pressurized liquid
to, and vent pressurized liquid from, the control chamber of the
sleeve valve 10. A passage 28 (FIG. 2) formed in a wall of the
sleeve valve housing 18 connects with a port 30 formed in the pilot
valve housing 26. The port 30 connects with a pilot valve chamber
32 formed inside the pilot valve housing 26. A passage 34 (FIG. 1)
formed in the sleeve valve housing 18 and the pilot valve housing
26 connects an inlet 36 (FIG. 5) of the sleeve valve housing 18 to
a port 38 (FIG. 2) in the end cap 24 which in turn connects to the
pilot valve chamber 32. The port 38 has a second end that opens at
39 on a side surface of the end cap 34. A relief passage 40 also
formed in the sleeve valve housing 18 connects to a port 42 (FIG.
2) in pilot valve housing 26 which in turn connects to the pilot
valve chamber 32. To simplify injection molding of the sleeve valve
housing 18, a cover 44 (FIGS. 2 and 3) is attached via suitable
adhesive or sonic welding to the sleeve valve housing 18 to form
passages 28 and 40. When the sleeve valve 10 is opened pressurized
water from the control chamber between the elastomeric sleeve 16
and housing 18 is released to the exterior of the sleeve valve 10
via relief passage 40 which terminates in a side opening (not
illustrated).
The non-latching solenoid 20B (FIG. 1) of the pilot valve 20 has a
construction similar to that disclosed in the aforementioned U.S.
Pat. No. 5,979,482, the entire disclosure of which is hereby
incorporated by reference. Referring to FIG. 4, the solenoid 20B
includes a main outer cylindrical shell or housing 46, a central
spool 48 and a pair of yokes 50 that surround the coil 22 (not
visible in FIG. 4) and enhance the magnetic field generated by the
coil 22. The region inside the housing 46 surrounding the coil is
filled with a suitable potting compound (not illustrated). The
solenoid 20B also includes a pole piece 52 that is secured in a
fixed position within the spool 48 at one end of the spool 48. A
cylindrical ferrous core plunger 54 acts as an armature and is
dimensioned for precision reciprocation inside of the spool 48
beneath the pole piece 52. A piston 56 has a shaft 56a whose upper
end is secured in a bore in one end of the plunger 54. The lower
end of the piston shaft 56a is connected to a piston head 56b. The
end cap 24 is secured to the lower end of the housing 46. A
cylindrical sleeve 58 mounted inside the end cap 24 also abuts the
lower end of the housing 46 and has a bore for receiving and
guiding the piston shaft 56a. A coil spring 60 surrounds that
sleeve 58 and is compressed between a shoulder 56c of the piston
and a radial flange of the sleeve 58. The plunger 54 and piston 56
are normally in their lower extended positions illustrated in FIG.
2 in which the sleeve valve 10 is closed when the coil 22 is not
energized. When the coil 22 is energized, the plunger 54 and piston
56 move upwardly to their raised retracted positions illustrated in
FIG. 3 in which the sleeve valve 10 is open. When the plunger 54
and piston 56 are retracted, the coil spring 60 is compressed. The
coil spring 60 ensures that the plunger 54 and piston 56 move to
their lower extended positions when the coil 22 is
de-energized.
The diameter of the lower segment 56d of the piston shaft 56a (FIG.
4) that is connected to the piston head 56b is greater than the
diameter of the upper segment of the shaft 56a that connects the
piston 56 to the plunger 54. A first seal 62 (FIG. 2) in the form
of an elastomeric ring surrounds the piston shaft 56a and is
secured to the upper side or end of the piston head 56b. The seal
62 seals the lower end of the port 38 in the end cap 24 when the
solenoid 20B is energized. A second seal 64 in the form of an
elastomeric disk is secured in a circular recess formed in the
lower side or end in the piston head 56b and seals the port 42 when
the solenoid 20B is de-energized. Advantageously, no seal is
required between the piston shaft 56a and the end cap 24. The
longitudinal axis of a bore 66 through the end cap 24 and the
longitudinal axis of the port 38 are parallel. The longitudinal
axis of the port 42 is co-axial with the longitudinal axis of the
bore 66. The lower end of the port 38 opens on the end surface of
the end cap 24. The lower end of the port 38 is spaced laterally
from the bore 66. The upper end of the port 38 opens on a side
surface of the end cap 24. The end surface of the end cap 24 has a
first land 68 (FIG. 2) that is spaced laterally from (and radially
outward of) the bore 66. The port 38 exits through a second land 70
formed on the end surface of the end cap 24. The seal 62 engages
the land 70 to provide a water-tight seal that closes the lower end
of the port 38 when the solenoid 20B is energized. The land 68
helps stabilize seal 62 and keep it perpendicular to the
longitudinal axis of the solenoid 20B.
The overall operation of the sleeve valve 10 can now be described.
When the solenoid 20B is not energized, spring 60 forces piston 56
downwardly to its extended position illustrated in FIG. 2. In this
position, seal 64 closes port 42 and seal 62 is disengaged from
land 70, opening port 38. Pressurized water from inlet 36 travels
through passage 34, through port 38 and into pilot valve chamber
32. This water then travels from the pilot valve chamber 32,
through port 30 and passage 28 into the control chamber of the
sleeve valve 10 between the sleeve valve housing 18 and the
elastomeric sleeve 16. Pressure builds up inside the sleeve valve
control chamber, forcing the elastomeric sleeve 16 inwardly and
sealing the slots 14 in mandrel 12. The flow through the main flow
passage of the sleeve valve 10 is now stopped and the sleeve valve
10 is in its closed state. When the solenoid 20B is energized, the
piston 56 is forced upwardly to its retracted position illustrated
in FIG. 3. The seal 62 closes off port 38, shutting off the source
of pressurized water from the inlet 36 through the passage 34. The
seal 64 is disengaged from the port 42. Water from the control
chamber inside the sleeve valve 10 to be expelled through passages
28 and 30 and into the pilot valve chamber 32. This water then
exits the pilot valve 20A via port 42 and relief passage 40. The
elastomeric sleeve 16 expands and water flows through the main flow
passage of the sleeve valve 10 which is now in its open state.
Port 38 is a high pressure port and is off-center from, but
parallel to the longitudinal axis of the solenoid 20B and its coil
22. The lower segment of the piston shaft 56a has a relatively
large diameter compared with the relatively small diameter of such
shafts in conventional three-way solenoid actuated pilot valves.
The piston head 56b and its upper seal 62 overhang the off-center
port 38. In conventional three-way solenoid actuated pilot valves,
the shaft of the piston has been a delicate pin. The diameter of
the piston head 56b and the diameter of the lower piston shaft
segment 56d do not have to be minimized as is the case with
conventional three-way solenoid actuated pilot valves. The port 42
is the atmospheric port and is centered relative to the
longitudinal axis of the solenoid 20B and its coil 22. The
advantage of the pilot valve 20A is that it can be opened and
closed with relatively low power compared to conventional three-way
solenoid actuated pilot valves. Moreover, it is easier to assemble
the larger piston 56 and related components of the pilot valve
20A.
The sleeve valve 10 includes smooth cylindrical end connections 72
and 74 (FIG. 1) for joining the valve with pipe segments (not
illustrated) using suitable solvent welding material. Female
threaded end caps 76 and 78 are used to secure the end connections
72 and 74 to male threaded ends 80 (FIG. 5) of the sleeve valve
housing 18. Together the female threaded end caps 76 and 78 and the
corresponding male threaded ends 80 (FIG. 5) of the sleeve valve
housing 18 provide what is known in the plumbing trades as unions.
The inlet 36 opens into an annular chamber formed when the end cap
78 is screwed over the end connection 74 onto the male threaded end
80 of the sleeve valve housing 18. A surface of the sleeve valve
housing 18 has radially extending grooves (not illustrated) that
filter grit to prevent it from clogging the small ports of the
pilot valve housing 26 and end cap 24. The smooth end connections
72 and 74 could be replaced with threaded or barbed end
connections.
FIGS. 6A and 6B illustrate an alternate embodiment 100 in first and
second states, respectively. The alternate embodiment 100 includes
a female threaded pilot valve housing 102 that screws over a male
threaded end cap 104 of a solenoid 106. A piston including a piston
shaft 108a and piston head 108b move up and down as the result of
the forces of a coil spring 109 and the energization and
de-energization of the coil (not illustrated) inside the solenoid
106, in a fashion similar to the prior embodiment described above.
The piston shaft 108a extends through a bore in the cap 104 and the
piston head 108b reciprocates up and down inside the pilot valve
chamber 110 formed inside the pilot valve housing 102. A port 112
extends through the center of the end of the pilot valve housing
102. A land (not visible in FIGS. 6A and 6B) is formed on an inside
surface of the pilot valve housing 102 surrounding the inner end of
the port 112 to facilitate the formation of a water tight seal when
a lower surface of piston head 108b is seated against the land. The
lower surface of the piston head 108b has an elastomeric disc 114
or other non-rigid member to enhance the water tight nature of this
seal, or the entire piston head 108b may be formed of an
elastomeric or other semi-rigid material. The piston head 108b
could have a rigid interior support structure and a soft outer
jacket or boot. A barbed fitting 116 is snugly inserted into the
outer end of the port 112. An L-shaped port 118 extends through the
end cap 104. One end of the port 118 communicates with a port 120
that extends through the side wall of the pilot valve housing 102.
Two O-rings 122 and 124 are seated in annular grooves formed in the
exterior of the end cap 104, and provide a water tight seal between
the mating ends of ports 118 and 120. Another barbed fitting 126 is
snugly fit into the outer end of the port 120. A serpentine port
128 also extends through the end cap 104 on a side of the piston
shaft 108a opposite to the port 118. A third barbed fitting 130 is
snugly fit into an outer end of the port 128. A land is formed on
the end surface of the end cap 104 and surrounds the lower end of
the port 118. When the piston head 108b is in its raised position,
an elastomeric seal 132 surrounding the piston shaft 108a and
resting against the upper side of the piston head 108b seals
against the end of the land surrounding the lower end of the port
118 to enhance the water tight seal established with the lower end
of the port 118. Another land, without a hole in the center
thereof, is formed on the end surface of the end cap 104 on a side
of the piston shaft 108a opposite to the location of the land that
surrounds the lower end of the port 118. When the piston head 108b
is in its raised position, the other side of the piston head 108b
strikes the end of this land to ensure that the piston head 108b
remains level, and that a water tight seal is established with the
land that surrounds the lower end of the port 118. However, when
the piston head 108b is in its raised position, the elastomeric
seal 132 does not seal the lower end of the port 128.
The operation of the solenoid actuated pilot valve 100 can now be
described. When the solenoid 106 is not energized, the spring 109
forces piston head 108b downwardly to its extended position
illustrated in FIG. 6A. In this position, the piston head 108b
seals port 112. In this state, ports 118 and 128 are in fluid
communication though the pilot valve chamber 110, and flow can be
established through hoses (not illustrated) connected to barbed
fittings 126 and 130. When the solenoid 106 is energized, the
piston 108b is retracted to its upward position sealing port 118 as
illustrated in FIG. 6B. This allows fluid communication between
ports 112 and 128 through pilot valve chamber 110. Thus, fluid can
communicate between hoses (not illustrated) which are attached to
barbed fittings 116 and 130.
Referring to FIGS. 7 and 8, a second alternate embodiment 200 of my
solenoid actuated pilot valve utilizes a solenoid 202 with a
reciprocating shaft 204 that is not permanently connected to the
head 206. The head 206 opens and closes the ends of separate ports
208 and 210 with the upper and lower sides of an elastomeric cover
212 that surrounds the head 206 in a fashion similar to that
described in conjunction with the embodiments illustrated in FIGS.
1-6B. The head 206 (FIG. 7) of the pilot valve 200 is formed with a
larger diameter lower disc section 206a (FIG. 8) and a smaller
diameter upper disc section 206b. The head 206 is integrally formed
with a drive shaft 214. The drive shaft 214 has a larger diameter
lower segment 214a whose lower end is connected to the upper disc
section 206b of the head 206. A cap 215 is press fit over the upper
end of a smaller diameter upper segment 214b of the drive shaft
214. The lower end of the upper segment 214b is connected to the
upper end of the lower segment 214a. A lower section 215b of the
cap 215 has a slightly larger diameter than the lower segment 214a
of the drive shaft 214. The drive shaft 214 and the cap 215 may be
formed of plastic or metal. The drive shaft 214 vertically
reciprocates in a bore formed in a generally cylindrical guide
sleeve 216 secured to the lower end of the solenoid 202 in
concentric alignment therewith. A small coil spring 218 surrounds
the lower segment 214a of the drive shaft 214 between the lower
segment 214a and the wall of the bore in the guide sleeve 216. An
upper section 215a of the cap 215 can seat on a shoulder formed in
the upper end of the bore through the guide sleeve 216 in order to
limit the downward travel of the drive shaft 214. The port 208
extends through the guide sleeve 216 between the central bore of
the guide sleeve 216 and the exterior of the guide sleeve 216. The
lower end of the guide sleeve 216 forms the upper wall of a pilot
valve chamber that encloses the head 206. The pilot valve chamber
can be alternately vented through ports 208 and 210.
The pilot valve 200 (FIG. 7) is actuated between two states and
functions as a 3-way valve by selecting alternate flow paths
between the ports 208 and 210 and a third port 230 (FIG. 7) that
communicates with the pilot valve chamber enclosing the
reciprocable head 206. FIGS. 7 and 8 illustrate the pilot valve 200
and the head 206 when the solenoid 202 is in its non-energized
state. When the solenoid 202 is not energized, a plunger 220 of the
solenoid 202 that is connected to the upper end of the shaft 204 is
forced downwardly by a large coil spring 222 whose lower end is
retained by a shoulder 204a (FIG. 8) on the shaft 204. The lower
end of the shaft 204 pushes downwardly on the upper cap section
215a to push the head 206 downwardly, compressing the small coil
spring 218, and causing the underside of the elastomeric cover 212
to engage a land 224 surrounding the upper end of the port 210.
This action seals off the port 210 and opens the port 208. When the
solenoid 202 is energized, the plunger 220 is drawn upwardly by the
electromagnetic field generated by its coil, pulling the shaft 204
upwardly and compressing the large coil spring 222. The lower end
of the shaft 204 disengages from the upper cap section 215a,
allowing the small coil spring 218 to lift the head 206. This
action presses the upper side of the elastomeric cover 212 against
a land 226 surrounding the lower end of the port 208. This seals
off the port 208 and opens the port 210.
While I have described several embodiments, each representing a
species of my generic solenoid actuated pilot valve, modifications
and variations thereof will occur to those skilled in the art. For
example, the port 42 could also be off-center. The design of the
solenoid 20B could be widely varied, such as by constructing it as
a latching solenoid. The size, shape and locating of the various
ports and passages could be varied to fulfill particular needs. The
end cap 24 need not be a separate piece but could be integrally
formed with housing 46. The piston 56 could be replaced with an
member that has a reciprocable longitudinally extending member
connected to a laterally projecting member for supporting two seals
on opposite sides thereof. For example, such a structure could be
provided by an L-shaped element similar in configuration to an
Allen wrench. One of the seals could be located on the upper side
of the laterally projecting member whereas the other seal could be
located on the underside of the longitudinally extending member or
on the underside of the laterally projecting member. The seals 62
and 64 could be over-molded elastomeric material, or they could be
non-elastomeric material such as regions of a head or other
laterally projecting member. The cap 215 may be securely fastened
to the shaft 214b using other methods such as threading the two
components, attaching with a screw, ultrasonic welding, solvent
welding, glue, heat staking or any other various methods to
securely attach two components together. The pilot valve of FIGS.
6A and 6B can be manufactured without the barbed fittings and
designed to mate directly to ports in a control valve similar to
FIG. 1. It will be further understood that while the pilot valve
housing 26 may be manufactured as a part of the sleeve valve
housing 18, a pilot valve sub-assembly including the solenoid 20B
with its specially designed end cap 24, piston 56 and seals 62 and
64 can be separately manufactured as a replacement part. My pilot
valve invention could be used with various configurations of sleeve
valves, diaphragm valves, and piston valves of the type commonly
used in commercial and residential irrigation systems. Therefore,
the protection afforded my invention should only be limited in
accordance with the following claims.
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